GBU12 missing targets by a few meters

[Dagger71]

 

Have a look at some real world wind charts before calling it "unrealistic and nonsense".

 

While not common, high winds at lower altitude do exists and they are directly correlated to surface wind (wind will be veering or backing as altitude increase depending if you're on the northern or southern hemisphere, and it will increase in intensity as your altitude increases)

 

A simple google search will shine some light on the subject if you're keen to discover it

 

I did hit the target on my second pass when aiming upwind. If you look at my F18 track you can see it yourself ;)

 

 

You had hurricane force winds at 6600feet!!!

[victorlima01]

Enough with the hurricane wind nonsense please. Those winds are not unrealistic. Just look at any winds aloft progx chart (hint: NOAA's aviation website) and you'll see that apart from the equator a wind ocmponent of at least 50 to 60kts is quite common starting in the upper flight levels. I've seen 150 kt tailwinds in the North Atlantic in FL350 - and it's not that uncommon. Two hours away from where I live there's a windsufing paradise where surface winds of 20-25kts with 35kt gusts are the norm.

 

With that said, I'm not privy to tactics in lasing where strong winds are expected. That does not mean sich a thing doesn't exist. That A10 vid posted above is the first I heard of it - again this just shows I haven't researched enough, and not that it isn't true. The tough thing is knowing what is a sim-ism (to quote Lex) and what's real tactics. Personally I always though the bomb owuld just whistle away towards the lased surface with enough kinetic energy in it.

 

(edited for grammar)

Edited June 7, 2020 by victorlima01

[Phantom453]

Just on a slightly different point.

 

I dropped four GBU 12 on non moving targets last night to try out the new auto lase function. While all my targets were destroyed, I'm sure I saw the auto-lase switch off on at least one occasion several seconds before impact.

 

Now my wind is only about 6 m/s at ground level, so ballistically it was probably going to hit a non moving target anyway, regardless of whether if the laser switched off several seconds before impact.

 

Obviously though, in higher wind conditions, or with a moving target, early disengagement of the laser will have more of an impact on missing the target.

 

Has anyone else notice the auto-lase switching off before impact? I'll test it a bit more today.

[Dagger71]

Enough with the hurricane wind nonsense please. Those winds are not unrealistic. Just look at any winds aloft progx chart (hint: NOAA's aviation website) and you'll see that apart from the equator a wind ocmponent of at least 50 to 60kts is quite common starting in the upper flight levels. I've seen 150 kt tailwinds in the North Atlantic in FL350 - and it's not that uncommon. Two hours away from where I live there's a windsufing paradise where surface winds of 20-25kts with 35kt gusts are the norm.

 

With that said, I'm not privy to tactics in lasing where strong winds are expected. That does not mean sich a thing doesn't exist. That A10 vid posted above is the first I heard of it - again this just shows I haven't researched enough, and not that it isn't true. The tough thing is knowing what is a sim-ism (to quote Lex) and what's real tactics. Personally I always though the bomb owuld just whistle away towards the lased surface with enough kinetic energy in it.

 

(edited for grammar)

 

 

again look at his winds he put in . He put 80 knots at 6600 feet! Which is a far cry from 50-60knots at upper levels! even 150kn winds at FL350 have nothing to do with GBU accuracy as you don't release GBUs at FL350! Enough with the nonsense.

Edited June 7, 2020 by Dagger71

[Dagger71]

 

This is taken from Mission 9 of the AFTQ campaign for the A-10C

 

Correction for LGB lasing is approx 1ft upwind per knot of wind

 

 

 

 

I don't think this is actually part of any NATOPS (F18 ) or AFI (A10C)

Edited June 7, 2020 by Dagger71

[Furiz]

Lmao at the wind theory.

 

Maybe its like that in game but it is a bug cause in real life the bomb will compensate on its own, you don't have to lead for it.

[Subferro]

Were you using autolase? In the OP video it looks like laser starts firing at 10 seconds TTI. Against a moving target in high winds, that won’t cut it.

 

Wind absolutely does affect lgb accuracy as has been demonstrated and documented multiple times in combat employment. I agree you don’t need to apply upwind lead to a stationary target, but you do need to change your lazing practice. Auto lase is probably not your friend in high winds.

[victorlima01]

again look at his winds he put in . He put 80 knots at 6600 feet! Which is a far cry from 50-60knots at upper levels! even 150kn winds at FL350 have nothing to do with GBU accuracy as you don't release GBUs at FL350! Enough with the nonsense.

 

You're right. I missed the 80 kts at 6000'. Could happen but not common at all - at least I've yet to see it.

 

 

 

I don't think this is actually part of any NATOPS (F18 ) or AFI (A10C)

 

But would Natops include tactical stuff?

[Fri13]

This is taken from Mission 9 of the AFTQ campaign for the A-10C

Correction for LGB lasing is approx 1ft upwind per knot of wind

[/Quote]

 

Not correction for lazing, but correction for bombing.

 

There is a difference.

 

When you drop a LGB, you will start lasering target only in final seconds before the bomb impact. Not before.

 

Before the lazing target, LGB is released and dropping by normal unguided bomb trajectory. There is no difference for physics.

 

If you have a wind, the wind will drag the bomb with it and change its trajectory.

And now you can have a situations that bomb seeker can't anymore find the laser spot when you start lazing. Or the bomb can be so far from it's energy state that it can't anymore use its fins to generate enough lift to push bomb to target.

 

It is same problem than if you start lazing target too soon, as the bomb will correct immediately its trajectory pointing the laser spot, and instead having loft trajectory, it has now a direct trajectory. And bomb will start to fight against it's own guidance that it cut short its flight curve. So the bomb fins would need to generate all the lift to move bomb laterally toward target, but it simply can't as it is not an missile with a range information.

 

As long the bomb can keep pointing its nose toward laser spot, it is believing it is on the track to target. Even if it would land on its belly and roll on ground, it would believe it is on the way to target.

 

So you will input wind correction to your targeting computer, so that it calculates you proper release point. So even if there would not be lazing, the bomb would drop near the target because it compensates for the wind.

But once the laser spot tracker detects laser spot, all is off. It doesn't matter what wind there is as the bomb is in the basket and it has trajectory and energy to guide to the laser spot.

 

It doesn't matter is there a wind or is there a moving target, the bomb will go there. But it all needs that you have proper release point. And that requires calculation of the wind speed and direction like as well from target speed, range and direction.

 

This was one of the great ARBS advances as it took all this in count when dropping bombs. The same system is in Shkval. Both systems measures target movement, angles, calculates distance from it and then reads out all the aircraft sensors for the wind, direction, speed, etc. And gives you an solution for dropping a bomb. As long the target keeps moving same speed and direction, it will be hit. As long wind blows at same speed and direction, bomb hits target.

 

But those systems ain't perfect, day time only and only for a wind information from the aircraft level. But that doesn't matter when you anyways fly low and not altitude.

 

But for that Russians built SVP-24 that reads atmosphere conditions from the aircraft all the way to the target, use the external informations etc and can bomb very accurately through multiple atmosphere layers with dumb bombs.

 

 

Have a look at some real world wind charts before calling it "unrealistic and nonsense".

 

While not common, high winds at lower altitude do exists and they are directly correlated to surface wind

 

80-90 kts wind is 41-46 metres per second wind.

 

A normal wind speed is 1-10 metres per second. From low to high.

A high wind is already 12 m/s that you have difficulties to move toward it and you can't hold umbrella.

A wind with 14-17 m/s brakes trees branches, moving outdoors is difficult.

Storm, 20-24 m/s wind brakes buildings, moves tiles and brakes windows.

24-28 m/s falls trees from their roots, severe damages to buildings.

28-32 m/s moves buildings, vehicles and falls while forests.

32+ m/s is hurricane, complete destruction on the area.

 

 

And you have wind that is an hurricane category 1 speed!

 

 

So, do you really believe that you are flying a combat missions in hurricane, bombing targets?

 

You are right that THOSE DO EXIST. But when those DO EXIST, it is emergency situation and no one is so stupid that they want to go flying there!

[Snakedoc]

Not correction for lazing, but correction for bombing.

 

There is a difference.

 

When you drop a LGB, you will start lasering target only in final seconds before the bomb impact. Not before.

 

Before the lazing target, LGB is released and dropping by normal unguided bomb trajectory. There is no difference for physics.

 

If you have a wind, the wind will drag the bomb with it and change its trajectory.

And now you can have a situations that bomb seeker can't anymore find the laser spot when you start lazing. Or the bomb can be so far from it's energy state that it can't anymore use its fins to generate enough lift to push bomb to target.

 

...

 

 

Agreed on the correction for aiming point, which is what I mentioned before and it is highlighted on the training mission briefing which I posted earlier, I'll attached it here again:

 

 

It is stating that "Adjust the laser aimpoint one foot upwind per knot of wind. In case of strong surface winds you may have to aim off target to record a hit"

 

I also agree on the concept of lasing too ealry/too late. In the test I am using auto lasing for the last 10 seconds which is in line with the recommendation for LGBs. I have also used manual lasing for the same last 10 seconds but the end result is the same *update* I have also manually lased for the last 20 seconds for longer guidance time in presence of wind and the bomb still falls downwind of the target

 

80-90 kts wind is 41-46 metres per second wind.

 

A normal wind speed is 1-10 metres per second. From low to high.

A high wind is already 12 m/s that you have difficulties to move toward it and you can't hold umbrella.

A wind with 14-17 m/s brakes trees branches, moving outdoors is difficult.

Storm, 20-24 m/s wind brakes buildings, moves tiles and brakes windows.

24-28 m/s falls trees from their roots, severe damages to buildings.

28-32 m/s moves buildings, vehicles and falls while forests.

32+ m/s is hurricane, complete destruction on the area.

 

 

And you have wind that is an hurricane category 1 speed!

 

 

So, do you really believe that you are flying a combat missions in hurricane, bombing targets?

 

You are right that THOSE DO EXIST. But when those DO EXIST, it is emergency situation and no one is so stupid that they want to go flying there!

 

Now, onto the wind values:

 

Yes, they are storm winds, I am well aware. We saw those winds speeds at altitude in Europe when flying around storm Ciara last winter. Some challenging landings at 30+ kts of crosswind I had to do in southern England and we weren't in any tactical mission, just a regular commercial line flight. With a surface wind in the region of 30kts, winds at altitude veers and increases in intensity, so yes even at 5000ft you can have speeds of around 40-50kts.

 

The only unrealistic setting which DCS weather engine imposes is an automatic assignment of the wind at 1600ft based on the surface wind. If you set a 30kts surface wind DCS will auto-set a steady 64kts wind at 1600ft which is unrealistic in my opinion and in my RL flying experience I have yet to see.

 

Would you go out on a tactical mission in the presence of those winds? Probably not, but here we are talking about a different subject.

 

 

 

So:

 

lets repeat the test with more mild winds. OP said he had a surface wind of 20kts, so here is the same mission and track file with the following winds:

 

 

surface 260/20kts

1600ft 260/43kts (auto-set by the mission editor, nothing I can do about this)

6600ft 265/25kts

26000ft 270/30kts

 

 

TGP designating exactly over the target (WYP1)

CCRP release at 425kts, approx 12500ft with auto-lase for the last 10 seconds. The bomb impacts downwind of the target because no upwind correction was applied, splash damage damages the BTR

 

attached track and mission file for anyone to have a go

 

I don't think this is actually part of any NATOPS (F18 ) or AFI (A10C)

 

You don't think or you don't know?

I have provided evidence of the wind correction for laser aimpoint based on one of the training missions prepared by Maple Flag. I have no idea where they sourced that information but so far it has been proven accurate and valid.

 

If you have an official (and unclassified) source of information that states that you don't correct for wind with LGB releases I will be more than happy to see it. So far the only published info I could find is the one from Maple Flag mission.

GBU12 wind test F18-20kts.trk

GBU12 mission wind test F18 20kts.miz

Edited June 7, 2020 by Snakedoc
updated testing

[Fri13]

It is stating that "Adjust the laser aimpoint one foot upwind per knot of wind. In case of strong surface winds you may have to aim off target to record a hit"[/Quote]

 

It is then wrong.

 

As your job as an pilot targeting a laser guided bomb is NOT to compensate for a wind speed OR target movement.

 

Your only job is to get bomb on proper RELEASE point. So that bomb will fly in a proper trajectory to the point when you start lazing target, that bomb trajectory is already optimal for it.

 

You will not move target designator off from the target to get bomb drop somewhere else than where you are aiming!

 

Do you know why? Because the weapon does not care what else that is where, as it only see the laser spot and it does everything in it's control surfaces to keep that point stationary by using proportional navigation.

 

In simple terms, when guided weapon moves and it can maintain laser spot stationary in it's gimbal limits, it is moving directly at it.

 

You can quote as much you want some DCS campaign story, but the bomb would NEVER drop accurately on anything if you need to start pointing laser designator toward wind to compensate bomb drop, because the bomb guidance system is then completely broken!

 

And the "minimum 8 second lazing" is another BS thing. You might not need any lazing at all if you drop it perfectly by using normal trajectory release if weather allows.

 

The GBU-12 etc are normal bombs that has laser guidance kit added to nose and extra control fins at the rear. They do generate extra drag and extra lift, so bomb doesn't accelerate as fast and it does catch wind more effectively, but it as well has capability to change bomb trajectory in given time.

What DCS doesn't model is the "bang-bang" guidance mode. What means that the LGB's with it should fly in waving manner, so it deflects fully it's control surfaces until it is over, then it deflects back to previous direction until it is over, and again... And each time the deflection time is shorter as the guidance system calculates time from correct direction to when it starts going back. And so on bomb falls down not straight like now in DCS, but moving around to the moment when it has got the trajectory corrected for straight trajectory and then it falls as is down.

 

And this is about that "8 seconds" BS thing. As in some cases the bomb trajectory can be so badly off that it needs to start doing long control times, going from one side to another and then back.

So if you drop bomb "out of basket" badly, it can't do anything. And and thing is if there is a hurricane wind going on, it's control surfaces can not generate such a lift that would allow it to drop toward in the hurricane wind of 41-46 meters per second.

 

The bomb does not care about wind. You do not care about wind in lazing phase. Only in the release phase you care about wind. And you don't need to care about lazing time if you get bomb released on the spot in the first place. But if your drop goes terrible wrong, you can laze even 60 seconds and bomb can't get to there.

 

The bomb guidance system has only one thing in mind, "Is the sexy spot in the darkness stationary?". And when it is stationary, it is going there if the trajectory is going there.

 

Why you can't drop normal bombs horizontally like a glide bombs or missiles (yes, there is a fancy video of it in DCS where the bomb glides like 15 km just nap on the earth to hit target), as they can not generate lift that holds them up in the air for horizontal flight until they are out of forward momentum and just drops sideways.

 

I also agree on the concept of lasing too ealry/too late. In the test I am using auto lasing for the last 10 seconds which is in line with the recommendation for LGBs. I have also used manual lasing for the same last 10 seconds but the end result is the same[/Quote]

 

Autolazing should take in count the pre-calculated trajectory, so if you loft bomb, it will stay up in the air far longer and turn toward target later, so autolazing should start lazing much further in time so it gets last 10 seconds of free fall in. While in dive bombing it starts earlier, and needs less time as bomb is already going toward target well.

 

Manual lazing does nothing extra for accuracy than if you start or stop too soon/late.

 

Now, onto the wind values:

 

Yes, they are storm winds, I am well aware. We saw those winds speeds at altitude in Europe when flying around storm Ciara last winter. Some challenging landings at 30+ kts of crosswind I had to do in southern England and we weren't in any tactical mission, just a regular commercial line flight. With a surface wind in the region of 30kts, winds at altitude veers and increases in intensity, so yes even at 5000ft you can have speeds of around 40-50kts.[/Quote]

 

30-50 kts is not a same thing as 80-90 kts.

 

The only unrealistic setting which DCS weather engine imposes is an automatic assignment of the wind at 1600ft based on the surface wind. If you set a 30kts surface wind DCS will auto-set a steady 64kts wind at 1600ft which is unrealistic in my opinion and in my RL flying experience I have yet to see.[/Quote]

 

The engine does just some simple math, as it is expecting some realistic starting values. It is like on layer 1 speed is X, then automatically set layer 2 speed X^1.6 etc.

 

30 kts is still 15 m/s, so completely realistic but not common.

 

Would you go out on a tactical mission in the presence of those winds? Probably not, but here we are talking about a different subject.[/Quote]

 

At 15 m/s I would, but not in 41-46 m/s.

And such speeds to see at higher altitudes is a hurricane forming up.

 

14–16 m/s near gale

17–20 m/s gale

21–24 m/s severe gale

25–28 m/s storm

29–32 m/s violent storm

≥ 33 m/s hurricane[/Quote]

 

9 m/s is already fairly severe crosswind for landing, requiring to carefully get aligned. But dropping bombs at that wind speed is not difficult if properly done.

 

So:

 

lets repeat the test with more mild winds. OP said he had a surface wind of 20kts, so here is the same mission and track file with the following winds:

 

 

surface 260/20kts

1600ft 260/43kts (auto-set by the mission editor, nothing I can do about this)

6600ft 265/25kts

26000ft 270/30kts

 

 

TGP designating exactly over the target (WYP1)

CCRP release at 425kts, approx 12500ft with auto-lase for the last 10 seconds. The bomb impacts downwind of the target because no upwind correction was applied, splash damage damages the BTR

 

attached track and mission file for anyone to have a go

[/Quote]

 

Need to check once getting back on computer in few days.

But clearly something is bugged.

 

You don't think or you don't know?

I have provided evidence of the wind correction for laser aimpoint based on one of the training missions prepared by Maple Flag. I have no idea where they sourced that information but so far it has been proven accurate and valid.

[/Quote]

 

For a unguided bombs yes. And that you can compensate by entering the values to FCS in A-10C or using ARBS that does it automatically.

 

But for laser guided bombs not capable to correct to 10.2 m/s sidewind is just laughable.

 

As you would NEVER hit any moving target then or never be able to drop bombs accurately on anything.

 

Just for your knowledge, 10.2 m/s is same as 36 km/h.

 

So go and try to hit a target that moves 36 km/h straight without turning.

As from bomb point of view it is exactly same situation.

 

I could do those things without any problems against 55 km/h targets, and there are people who put bombs against fighters flying in air in DCS.

 

But wind does not require you to compensate off-target by hand, as the whole guidance and designation system has been designed to exactly avoid all that!

 

If you have an official (and unclassified) source of information that states that you don't correct for wind with LGB releases I will be more than happy to see it. So far the only published info I could find is the one from Maple Flag mission.

 

Do you even understand what is proportional guidance law?

 

From the bomb point of view it doesn't matter does target move or does the air move. It has only one simple tasks, keep the laser spot stationary....

[Photon]

Well, the mission editor creating a wind-shear basically, at 1,600' no matter what you want, is a bit odd I would say.

I think if the winds are tapering off more normally from top to bottom the bomb wouldn't get the insane wind-shift at 1,600' to deal with

[Subferro]

If you have an official (and unclassified) source of information that states that you don't correct for wind with LGB releases I will be more than happy to see it. So far the only published info I could find is the one from Maple Flag mission.

 

 

https://www.airuniversity.af.edu/Portals/10/AUPress/Books/B_0074_OWEN_DELIBERATE_FORCE.pdf

 

Has a whole section on lessons learned regarding LGB employment in high winds. No mention of offsetting aim points, but in summary terminal end game lazing does not work in a high wind scenario, regardless of your fancy computer correcting for winds...

[QuiGon]

in point track? please show me a track of you doing this.

No, not in point, but in manual tracking of course.

[Snakedoc]

https://www.airuniversity.af.edu/Portals/10/AUPress/Books/B_0074_OWEN_DELIBERATE_FORCE.pdf

 

Has a whole section on lessons learned regarding LGB employment in high winds. No mention of offsetting aim points, but in summary terminal end game lazing does not work in a high wind scenario, regardless of your fancy computer correcting for winds...

 

Very interesting study thank you!

 

I quote some of the text I found on this document related to LGB employment in high winds. As you said no mentioning of aimpoint technique unfortunately

 

 

p.320/321

...Attacking from 20,000 feet at 0.9 Mach, the aircraft

would release the LGB approximately five nautical miles from

the target...

 

.. Just prior to the end of the LGB’s time of flight (TOF), the WSO would fire the laser

and self-designate his own weapon to impact. Initially, the

F-15Es used a terminal-delay lazing technique (final portion of

TOF), but after a few misses, possibly due to high-wind (about

75 knots!) corrections at end game, aircrews adopted a con -

tinuous lazing technique to allow the weapon to make more

constant adjustments from the wind effects, thus improving

their hit rates...

 

p.322

...Like that of the F-15E, the F-16’s typical

LGB delivery profile entailed two-to-four-ship, medium-altitude,

delayed-lazing tactics. From a 40,000-foot slant range from

the target, the F-16 released the LGB and cranked for a

split/offset away from the target. After acquiring the target

with help from the targeting pod, the pilot fired the laser prior

to the end TOF of the weapon. The LGB would travel nearly

five nautical miles before impact.

Early on in the air campaign, the F-16s experienced less

than-optimum results from their GBU-10 (2,000 lb) deliveries.

Given their limited experience in employing this weapon, even

the best of the pilots still missed about 50 percent of the

drops. Like their counterparts in the F-15Es, F-16 pilots were

not allowing enough time for their GBU-10s to acquire the

laser energy and make upwind corrections. Consequently, the

31st Fighter Wing changed from GBU-10s to GBU-12s (500 lb)

where weaponeering allowed. In addition, the use of GBU-12s

allowed the F-16s to return to Aviano without jettisoning their

bombs in the Adriatic Sea .

After consulting with the Fighter Weapons School at Nellis

Air Force Base (AFB), Nevada, fighter-weapons personnel of

the 31st Fighter Wing decided not to change to continuous

lazing with GBU-10s, as had the F-15 pilots, because the

school was teaching end-game delayed lazing. Instead, they

opted to substitute weapons that might have compromised

weaponeering at times because the probability of kill was less

with the GBU-12s. What could they have learned from LGB

employment history? For one, delayed lazing developed from

high-speed, low-altitude, loft-delivery techniques—not a medium-altitude technique (in which low ballistic energy and

premature LGB pitchovers were concerns)...

 

 

 

Taken from the above I changed my release parameters on the same 20kts test mission I posted earlier and instead of releasing the GBU12 at higher altitude I did it with the following parameters:

 

• low-altitude (5000ft), high speed (550kts), auto-lase 10sec and boom, right on target!
  

 

interestingly enough then I tried:

• 13000ft, M.95 release with continuous-lasing (simulating what the F15 crews did from the study did during Deliberate Force in Bosnia) and boom, right on target again. :)
   
  

 

 

 

I tried next with stronger winds so I loaded up the 30kts surface wind test mission:

 

• low-altitude (5000ft), high speed (550kts), auto-lase 10sec, the bomb lands downwind of the target so upwind correction is still a factor here.
  

 

• 13000ft, M.95 release with continuous-lasing, GBU-12 lands downwind of the target so upwind correction is still a factor here.
  

 

• However, I then tried a high speed (550+kts), low altitude (4000ft) release with continuous-lasing and even with 30kts of surface wind, boom! right on target :) upwind correction is not a factor here
  

 

 

 

I guess then it's a combination of factors which depends on various release parameters. In some cases of strong surface winds upwind correction is needed, some other times if coupled with more kinetic energy at the release point plus continuous-lasing technique then is not needed. This is possible on the F/A-18C because is capable of high speed flying, in the warthog however upwind correction is a more incisive factor due to its slower speed.

 

 

 

The more you know :)

Edited June 8, 2020 by Snakedoc
grammar

[Flagrum]

The whole idea of LGBs is that they hit where the laser is aimed at.

 

 

The variable part is the bomb trajectory to get to that point. If lased too late, the bomb might have not enough time to correct it's trajectory if wind has blown it off course. So you can either lase earlier, but you risk that the bomb loses too much energy to be able to fly it's straight line towards the target and falls short or gets blown off course as well.

 

Or you can try to compensate the wind effects by aiming the ballistic trajectory up-wind so that in the end the bomb is right on target and has only to do minor corrections for hitting the laser spot. You would probably do this by using CCIP and aim manually up-wind.

But the laser should always stay on the intended target. If you misuse the laser for the wind correction, you only add yet another factor of uncertainity. Why lase at all in this case? Just aim it manually, if you don't even intent to hit the laser spot at all?

[PL_Harpoon]

All of this makes sense actually.

 

 

I doubt that LGB's compensate for wind speed when they fall. I was always under the impression that they just keep pointing at the target and adjust for any offset in real time.

Sort of like a straight pursuit.

That should be enough if the wind is too strong or the target isn't moving too fast.

 

But if those conditions aren't met then the straight pursuit isn't sufficient to keep them on track.

[Snakedoc]

All of this makes sense actually.

 

 

I doubt that LGB's compensate for wind speed when they fall. I was always under the impression that they just keep pointing at the target and adjust for any offset in real time.

Sort of like a straight pursuit.

That should be enough if the wind isn't* too strong or the target isn't moving too fast.

 

But if those conditions aren't met then the straight pursuit isn't sufficient to keep them on track.

 

Yes indeed that's the exact logic behind the LGB. :thumbup:

 

The whole idea of LGBs is that they hit where the laser is aimed at.

 

 

The variable part is the bomb trajectory to get to that point. If lased too late, the bomb might have not enough time to correct it's trajectory if wind has blown it off course. So you can either lase earlier, but you risk that the bomb loses too much energy to be able to fly it's straight line towards the target and falls short or gets blown off course as well.

 

Or you can try to compensate the wind effects by aiming the ballistic trajectory up-wind so that in the end the bomb is right on target and has only to do minor corrections for hitting the laser spot. You would probably do this by using CCIP and aim manually up-wind.

But the laser should always stay on the intended target. If you misuse the laser for the wind correction, you only add yet another factor of uncertainity. Why lase at all in this case? Just aim it manually, if you don't even intent to hit the laser spot at all?

 

Agreed and that would make sense also if the target would be lased by someone else, you'd just worry to drop the bomb "dumb" as accurate as you can over the target, manually aiming upwind using CCIP. Then once locked onto the laser it would just track the target doing minimal corrections.

 

 

However, all the release in these tests are done in CCRP and I think the issue is the Release point of the bomb and it's kinetic energy at that moment.

 

 

When you designate the target using the TGP (in the hornet) to then drop a bomb in CCRP as far as I know it doesn't account for any wind, and the Release Point is calculated with ballistic trajectory.

To follow your suggestion you'd have to drop the bomb "late" past the CCRP calculated auto-released point to have the bomb falling ballistic over the target and then use the laser to aim it at the target and it makes sense!

 

In case of strong surface wind, if you drop the bomb at the "no-wind" CCRP release point it may not have enough energy to correct its trajectory with the laser and land downwind of the intended point. If you correct your laser aimpoint upwind it would solve this problem

 

Now I don't know if you can tell the a/c what's the surface wind for CCRP release or if it takes it automatically, I think in the A10C you can but I am not too familiar with the procedure.

This could probably explain why in the maple flag mission it says to aim upwind even for LGB, in order to get a "wind corrected" CCRP release point without going into too much details for the wind correction in the CDU.

 

*update*

 

I tried in the same 30kts surface wind test mission with this conditions:

 

• 13000ft, M.095, no upwind correction
  

• I waited to pass the CCRP release point and then dropped the bomb late (eyeballing it)
  

• Continuous-lasing until impact but the bomb still falls downwind of the target
  

 

• I also tried to designate a TGT point upwind of the target to have an accurate Release point cue, released the bomb, slew the TGP back on the target, lasing but the bomb still falls downwind.
  

 

at this point lasing upwind seems to be the most effective technique to record a hit with strong surface winds under certain release parameters

Edited June 8, 2020 by Snakedoc
updated testing

[Fri13]

So as I said, that they didn't have a wind speed corrections like A-10C does, that changes the delivery release point for proper lazing in terminal phase as bomb does fall already very close to target.

 

And that depending release parameters, you might need to laze target earlier or later so that seeker and control fins has enough time to react target movement.

 

There is a reason why GBU-12 ain't great against moving targets as it has no logic to estimate target position in future, why F-35 will get GBU-46 bombs that includes that capability to track moving target and generate a predictive impact point and fly there.

 

As from bomb point of view the target is same as moving when side wind exist, and if the basket when lazing happens is not closed enough, the bomb has no means to correct itself anymore.

 

And even 75 knots wind is not impossible at 20'000 altitude, but it sure is no-go for 1600' altitude.

 

That is 38 m/s at 6km altitude, and not at 500m altitude, as that is hurricane wind speed.

 

At higher altitudes you can have even higher per second speeds, while at ground or middle altitudes there is a calm weather.

The known fastest speed was in hurricane over 110 m/s.

 

But you should know the weather when you go to combat.

 

 

We need to a well understand what software version do we have in each aircraft, that do they have at the time a wind correction capability by what means.

 

But as it was already above mentioned, US pilots didn't know how to use bombs and they missed often.

So again, training, training and training....

[Fri13]

All of this makes sense actually.

 

 

I doubt that LGB's compensate for wind speed when they fall. I was always under the impression that they just keep pointing at the target and adjust for any offset in real time.

Sort of like a straight pursuit.

That should be enough if the wind is too strong or the target isn't moving too fast.

 

But if those conditions aren't met then the straight pursuit isn't sufficient to keep them on track.

 

Exactly, up to some limits the bombs guidance systems works, if you release bombs as well correctly.

 

But this is bug if any wind causes GBU to miss in proper release method.

[Fri13]

 

at this point lasing upwind seems to be the most effective technique to record a hit with strong surface winds under certain release parameters

 

That should be bug because if bomb has maneuvering capability after its release to reach the impact point, then it should never need any laser adjustments away from target to upwind as it doesn't help at all.

 

It seems that bomb ballistic trajectory is calculated from the laser spot, not from the bomb release point, why wind speed affects the terminal guidance such a way that it is affecting off-axis between those two. And if bomb doesn't have any aerodynamic capabilities guide itself to target position once lazing starts, then or shouldn't matter do you laze how much upwind as bomb simply can not reach target.

 

The wind speed changes only that, bomb capability to fly given area after release, not its accuracy to impact on laser spot inside that area.

Why wind speed changes only your release and your lazing parameters.

[Snakedoc]

That should be bug because if bomb has maneuvering capability after its release to reach the impact point, then it should never need any laser adjustments away from target to upwind as it doesn't help at all.

 

It seems that bomb ballistic trajectory is calculated from the laser spot, not from the bomb release point, why wind speed affects the terminal guidance such a way that it is affecting off-axis between those two. And if bomb doesn't have any aerodynamic capabilities guide itself to target position once lazing starts, then or shouldn't matter do you laze how much upwind as bomb simply can not reach target.

 

The wind speed changes only that, bomb capability to fly given area after release, not its accuracy to impact on laser spot inside that area.

Why wind speed changes only your release and your lazing parameters.

 

 

some of this makes sense, but then why is the bomb missing the target if lased onto it in presence of strong winds?

 

 

The study on Deliberate Force in Bosnia posted earlier says that real military pilots back then had issues in dropping LGB in high winds and had to change their delivery parameters to record better hits

 

 

If you look at my post #40 I tried to change the release technique and lasing-timing reproducing what was discovered in that study and I was able to hit the target without lasing upwind. You need however a low altitude and high speed plus continuous-lasing to give the bomb the energy and time needed to maneuver itself, and this may not be possible during some deliveries (e.g. low-level threats, a/c type, etc)

 

 

So I think that the lasing upwind technique is more relevant to high altitude, "slow" speed release like for example if you drop it with the A-10C and that's why this technique is mentioned in that training mission.

 

I don't think they would insert such a statement if this wouldn't be accurate and the initial release of that campaign was around 2015. It would be interesting to know where they sourced that information, maybe the original designers of that campaign can chime in?

 

I know DCS has an history of long-lasting bugs but I don't think this is a bug at all. There are also a couple of other threads discussing this where they mention this upwind correction, they are quite old but they exists:

 

• What are the wind speed limitations of LGB ordinance?
   
  
• LGB help
  

 

I'm not saying that lasing upwind is the only technique to be used in case of LGB releases in high-winds, but in some cases it is needed if you don't give or you can't give the bomb enough energy and/or time to correct itself onto the target.

 

 

Now, what is odd is the auto-set windshear at 1600ft that DCS imposes based on the surface wind which again, in my opinion is somewhat unrealistic.

 

For a surface wind of 30kts, DCS auto-sets a 64kts wind at 1600ft, that is a lot. But this is OT

Edited June 9, 2020 by Snakedoc
typo

[PL_Harpoon]

That should be bug because if bomb has maneuvering capability after its release to reach the impact point, then it should never need any laser adjustments away from target to upwind as it doesn't help at all.

 

It seems that bomb ballistic trajectory is calculated from the laser spot, not from the bomb release point, why wind speed affects the terminal guidance such a way that it is affecting off-axis between those two. And if bomb doesn't have any aerodynamic capabilities guide itself to target position once lazing starts, then or shouldn't matter do you laze how much upwind as bomb simply can not reach target.

 

The wind speed changes only that, bomb capability to fly given area after release, not its accuracy to impact on laser spot inside that area.

Why wind speed changes only your release and your lazing parameters.

 

 

Not necessarily.

 

From the bomb point of view going against the wind is just like chasing a moving target.

 

So on my picture in trajectory A you aim your laser at the tank and let the bomb chase it.

On trajectory B you aim laser at the point where the tank will be at the impact point.

Clearly, trajectory B is much more energy efficient.

 

Now, to go back to the wind, if you aim upwind it's just like choosing trajectory b in the picture.

 

 

My only question is, should the Hornet take the wind into account when calculating release point or not?

[jojo]

I don't know if DCS simulate this.

But IRL, Paveway II control surfaces are all or nothing.

Each time the guidance kit make a correction, the guidance kit control surfaces go full deflection, so each correction produce drag which depletes bomb's energy, and it may fall short.

This is way the preferred method is to delay the illumination, guiding the bomb only in terminal phase preserves the bomb energy and maneuvering capacity.

 

The aircraft release system should compensate for the wind.

But if there are wind shears in various level of altitude, the bomb may drift outside of guiding parameters and miss.

 

IMHO, with strong winds, releasing down wind makes more sense.

 

At the end, GBU-12 may not be the best suited weapon for moving targets. You have AGM-65 for that purpose.

Edited June 10, 2020 by jojo

[PL_Harpoon]

wings, releasing down wind makes more sense.

 

At the end, GBU-12 may not be the best suited weapon for moving targets. You have AGM-65 for that purpose.

True, but you can have twice as much GBU-12s as MAVs.